Start-stop repeater system



April 1940- 1.. M. POTTS START-STOP REPEATER SYSTEM Original Filed Nov. 50, 1934 Ill/447% ATTORNEY.

Patented Apr. 2, 1940 PATENT OFFICE START-STOP REPEATER SYSTEM Louis M. Potts, Evanston, Ill., assignor to Teletype Corporation, Chicago, 111., a corporation of Delaware Original application November 30, 1934, Serial No. 755,253. Divided and this 16, 1937, Serial No. 154,056

9 Claims.

This invention pertains to telegraph systems and apparatus and more particularly to telegraph repeating systems utilizing a plurality of telegraph repeaters.

In telegraph repeating systems where transmission is efiected at high speeds, it becomes necessary to provide apparatus to preserve the rela tive lengths of signal impulses as well as to reestablish the current strength thereof. Accordingly, regenerative repeaters have been designed for start-stop telegraph systems in which received signal impulses are reproduced and retransmitted in renewed strength and in faithful reproduction of their relative time values, thereby producing signal impulses and signal conditions equivalent to the originally transmitted signals. Transmission systems in which such repeating apparatuses are connected usually efiect transmission in both directions over a single line Wire, and in such systems, it is required that any repeating apparatuses connected between two sections of a line repeat from either line section into the other in response to an initiation of transmission of signals in either line section, and

" it is required further that a repeated signal shall not be repeated or reflected.

An object of the present invention accordingly is to provide an impulse repeating system employing repeaters capable of operating at high,

30 speeds to transmit signals under the control, of either line section into the other line section equivalent in strength and wave shape to the originally transmitted signals, and to provide means for reflection estoppel.

The above and other objects of the present invention are attained by provision of motor-driven signal-controlled repeaters for repeating all signal impulses including start and stop signal impulses and character-code signal impulses from one line section to another with elements controlled by mechanical power for establishing refiection estoppel conditions.

Specifically, the apparatus of the invention comprises electrical circuits of impulse-repeating and reflection-estoppel nature, both controlled by electrical switches which are controlled jointly or in common by motor-driven start-stop cams.

The circuits of the present invention in which directional control is exercised comprise magnets and contacts of two regenerative repeater apparatuses so associated in retransmitting and reflection-estoppel circuits that the operation of either repeater apparatus sets up a repeating condition and an estoppel condition which prevents application July operation of the other repeater and thereby prevents reflection signals.

A better understanding of the invention may be had from the following description taken in connection with a copending application Serial No. 755,253 filed by Louis M. Potts November 30, 1934 for Start-stop repeater system of which copending application the present application is a division, and further in connection with the accompanying drawing, wherein, v

Fig. 1 shows a circuit system comprising two line sections connected together through two combination printers and regenerative repeaters having polarized line magnets, the system operating upon two-current principles using polar signal impulses, transmission from a first termi nal station to a second terminal station being also recorded upon one printer at a repeating station, and transmission in reverse direction from the second terminal station to the first terminal station being recorded also upon another printer at the repeating station; and i Fig. 2 shows a circuit system comprising two line sections connected together through two combination printers and regenerative repeaters having neutral line magnets, the system operating upon single-current principles in which signal impulses comprising time periods of current are separated by signals comprising time periods without current.

As disclosed in Fig. 1, a system according to this invention embodies two terminal stationsA and B having their individual lines 2 and 3 respectivelyrterminated at a repeating station C. Each of the terminal stations is provided with a receiving printer 4 of polar-control construction anda transmitter 5, both receiving printer 4 and transmitter 5 being suitable for transmission under two-current principles. Receiving printer 4 is provided with a two-position armature 6 which takes one or the other of its two positions according to the polarity of the instant controlling cur rent. Transmitter 5 is provided with a battery of positive or marking polarity connected through resistor l to a contact in transmitter 5 and with a battery of negative or spacing polarity connected through resistor 8 to a contact in transmitter 5. The details described are shown diagrammatically at terminal station A, while terminal station B is similarly equipped. There is also arranged .at each of the terminal stations an interrupter key 9 connected in the circuits of the terminal station in such manner that when in its operated position it will disconnect the receiver printer 4 and the transmitter 5 from the line 2 and will connect the line 2 to negative or spacing battery through resistor 8, also a motor H supplied with electrical energy over a circuit (not shown) serving to supply motive power to the receiving printer 5 and transmitter 5 as is well known. The circuit of the driving motor ll may be controlled automatically by telegraphic signals in the line 2 as is well known.

As previously indicated, each of the lines 2 and 3 extends from the respective terminal stations to the repeating station C, and included in each of the lines is a line magnet l2 and [3 re spectively. These line magnets are normally energized from batteries at the terminal stations A i and B under control of contacts in transmitter 5 at each of the terminal stations. The circuit for eiiecting the energization of line magnets l2 and i3 extends in the case of terminal station A from ground at repeating station C, through resisto: winding of magnet 12, contacts i5, line 2,

spring and lower contact of-interrupting key 9, winding of receiving printer magnet l, transmitter 5, and resistor a to positive or marking battery. A circuit for line magnet l3 may be traced similarly through resistor 46, contact IT, and line 3 to terminal station B and to positive or marking battery.

Polar magnet i2 and its armature 2| com prise a selector magnet of a start-stop regenerative repeater 20 of the form and construction shown in Patent No. 2,104,273 granted Jan. 4, 1938, to L. M. Potts.

According to the disclosure of the aforementioned patent, the regenerative repeater is similar in construction to the printing telegraph device described in Patent No. 1,821,110 issued to S. Morton et al., September 1, 1931, and embodies a cam drum 22 arranged with the stop arm 23 normally in engagement with a fixed stop 24. The cam drum 22 has six pairs of cams 25 which control six selecting levers 26 in accordance with six received intelligence impulses to operate the selector levers in sequence to register each intelligence signal impulse of a code as the impulses are received, after which a transfer action occurs to transfer the six registrations simultaneously to the selector mechanism and to the printing mechanism of the receiving printer. Also carried by drum 22 are two multiple cam rings 36 and 3!, which are shaped to represent all of the cams 25 and in longitudinal alignment therewith, and two additional cams representing start and stop signals of a start-stop code. Arranged in coaxial alignment with the six selector levers 26 is a repeater selector lever 32 moved into marking and spacing positions in a manner similar to the operation of selector levers 25 but operating for every impulse of the entire code signal including the start and stop impulses. With every movement of lever 32, a striker 33 is operated to change the contactive relation of contact members 34, 35, and 36 for the purpose of transmitting impulses in a controlled line section corresponding in strength and wave shape to the impulses received for controlling the operation of cam drum 22. Normally, cam drum 22 is in its marking position with selector magnet l2 energized by current of marking nature, in which case the stop arm 23 is in engagement with the fixed stop 24. Upon receipt of a spacing signal indicative of a start condition generated by transmitter 5 at terminal station A, selector magnet l2 will be energized to move its armature 2|, which will permit cam drum 22 to free stop arm 23 from fixed stop 24, andsince driving motor 31 is now supplying power to the regenerative repeater, having been started automatically in any well-known manner in response to the change of signal in magnet l2, cam drum If?! is likewise rotated. Selecting magnet i2. and its armature 2| will respond to the operation oi transmitter 5 at terminal station A and cause the cam drum 22 to be moved correspondingly and thus bring the cam rings 30 and 3! into operative relation with the selector lever 32 for causing the corresponding operation of contact members 34, 35, and 36. Simultaneously with the operation of selector lever 32, the selecting levers will be operated through cams 25 for setting the selector mechanism of the printer to record the corresponding characters. The operation of contact members 34, 35, and 36 will generate in the line conductor 3 connected thereto impulses corresponding to the impulses which effected the ener gization of selecting magnet [2.

Assume that terminal station A desires to transmit a message to terminal station B, interrupter key 9 will be momentarily o erated into its reverse position, resulting in the reversal of polarity of the current in line 2 and in the reversal of polarity of the energized polar selector magnet H! at the repeating station C. Motors H and 3'! are started automatically by means, not shown. and motive power thus is applied to transmitter -5 and receiving printer 20. Also as a result of the momentary operation of interrupter key 9. line magnet l-2 reverses the position of its armature 2|, thus releasing cam drum 22 which. by a slight axial movement, frees stop arm '23 from its fixed stop 24. Immediately thereafter :1. cam oi multiple-cam ring 3| engages repeater selector lever 32, which responds and moves striker thus changing the contactive relations of the contact members 34, 35, and 35, opening repeating contacts H and closing repeating contacts 38 and thereby changing the signal current in line 3. The circuit for current in line 3 now xtends from positive battery 39 of double potential value through resistor 4i, closed contacts 38, line 3, interrupter key, receiving printer magnet, transmitter contacts, and resistor of terminal station B and through positive battery of single potential value to ground. Normally, line 3 carries a current in marking direction which causes the printer magnet to hold its armature in nonoperating position, but in the circuit just traced. the double potential of marking battery 39 at the repeating station C overpowers the single potential of marking battery at terminal station E. thus reversing the direction of polarity of current in line 3 and through the printer magnet of st tion B. The printer magnet of terminal station B reverses its armature and starts its motor. Upon restoration of interrupting key 9 at terminal station A, the normal marking current is restored to the line 2, the magnet l2 reverses its polarity and restores its armature at the repeating station C, shifting the cam drum 22 which causes selector lever 32 to return to its normal position, restoring the repeating contact members 34, 35, and 35 to their normal positions, closing repeating contacts IT, and opening repeater contacts 323, thus restoring the normal condition of circuit and current to line 3, restoring the marking polarity to the receiving printer magnet at the terminal station B, which returns its armature to its normal position. All needed motors having been started by this operation of the interrupting key 9 at the terminal station A, the operator at station A may send a message.

Movement of transmitter 5 connects its tongue to spacing contact to transmit a starting impulse of a code signal and connects negative battery through resistor 8 and transmitter 5, receiver magnet 4, key 9, line 2, contacts 15, magnet 12 f repeater 20, and resistor l4 to ground, thus reversing to spacing position the armatures 6 and 2| of magnet 4 and of repeater magnet l 2 respectively. The reversal of armatureZl shifts cam drum 22, reverses the position of lever 32 and reverses the contactive relation of contact members 34, 35, and 36, thereby connecting positive battery 39 through repeater contacts 38 to line 3, through printer magnet and transmitter to positive battery and ground whereby the double potential of battery 39 overcomes the potential of the terminal station battery and reverses the position of the armature of printer at station B into spacing position, thereby repeating at terminal station B the signal originated at terminal station A. Meanwhile, movement of contact 35 away from contact 34 has opened the circuit of the magnet l3 of the repeater of line 3 which, having apolarized armature with a permanent field, is held by its permanent field in its marking condition and which, therefore, does not repeat the spacing condition into the line section 2, The magnetic field of magnet l3 therefore constitutes areflection estoppel means. When transmitter 5 restores its tongue to its marking contact at the termination of the starting spacing signal, positive battery at terminal station A restores the direction of current in line section 2, restores armature 2| to its marking condition, which restores cam drum 22 to marking condition and in timed relation to the beginning of the starting impulse of a ring 30 will restore repeater lever 32 to its marking condition, which restores con-' tact members 34, 35, and 36 to the contactive relation illustrated, thus removing line wire 3 from source 39 and restoring it to groundconnection through the magnet l3, thereby supplying marking current again to the magnet I3 without operating its armature since it has 'remained in marking position, and also restoring current from positive battery at terminal station B to central oflice ground through the magnet of the repeater at terminal station B, thereby restoring the armature of that transmitter to marking condition, thus repeating in the printer at terminal station B the restored marking signal originated in transmitter 5 at terminal station A. Interruption of transmission may be effected by shifting the tongue of the interrupting key at terminal station B to its spacing contact for a short period of time, thus connecting nega tive battery to line 3 whereupon either forthwith or at the end of the instant signal, if spacing, the negative battery at terminal station B will become effective and will reverse the signaling condition of the repeater magnet l3 starting its motor and reversing its repeating contact mem bers, and thus will connect double marking potential 39 through line 2 to terminal station A, after which the printer 4 at substation Awill be unresponsive to the transmitter 5 since current from battery 39 will flow in spacing direction through the magnet of printer 4 in either position,

of the tongue of transmitter 5 and through either of the terminal station batteries at station A to ground, by which non-response of printer 4, the operator at terminal station A will note that terminal station B is interrupting and desires to transmit. h

During all interchange of transmission between the two terminal stations A andB, an transmis'- sion originated at station Awill-operate magnet l2 of printer 20 and will be recorded upon printer 20, while all transmission originated at station B will operate magnet I3 and will be recorded'up'on the printer of magnet'l3. Thus at the repeat-j ing station 0, the direction of transmission whether from terminal station A or from ter minal station B will be indicated and identified by the identity of the printer at station C upon which the transmission will have been'recorded;

In Fig. 2 is disclosed a'system according to this invention embodying two terminal stations "D andE having their individual lines 42 and 43 respectively terminated at a repeating station E. Each of the terminal stations is provided with 'a receiving printer 44 of neutral-control construct 7 'missionunder single-current principles; Termie nal station E is similarly equipped. There'is also arranged at each of the terminal stations-D and E an interrupter key 46 connected-in series'w-ith the line circuit to open the line circuit, also a motor 41 which'may be controlled automatically by line signals through means not shown. As'in the case of the system of Fig. lyeach of the lines 42 and 43 extends from the respective terminal stations to the repeating stationF'a'nd included in each of the lines is 'a line magnet 48' and 49 respectively, which are normally energized from batteries adjacent thereto. The circuit for effecting the 'energization ofthe line magnet 48 extends from battery through magnet 48, con' tacts 5|, line 42, interrupting :key to, .printer magnet 44, and closed contacts'of transmitter 45 to ground at terminal station D. Asimilarrcircuit may be traced through line magnet 49, con

which operates asa printer and also operates its repeating contact members 55 and its repeating contacts 52 and 56 in the manner which has been described above in connection with the description of Fig. 1. r i

Assume that terminal station D desires to transmit a message to terminal station E, interrupter key 46 will be mo'mentarily operated, which opens its contacts thus opening the circuit of line 42, resulting in the deenergization ofmagnet 48 and the release of its armature 53 at the repeating station Motors 41 and 51 are started automatically by means, not'shown, and motive power thus is applied to transmitter and receiving printer 54; Also, 'release'of armaturet53 has released the cam drum of printer 54, which shifts axially and starts into rotation. Immediately thereafter its repeater selector lever changes the contactive relations of its contact members 55, opening repeating contacts 52 and closing repeating contacts 56. Normally,"line 43 carries current as a marking signal which causes the printer, at terminal station E to hold its armature in non-operating position, but since the circuit of line 43 has been opened-at contact 52, the line current ceases, thus releasing the'armature of the printer and starting themotor atterminal station E, M Upon, restoration of interrupting key 46, the normal marking current is restored to line 42, magnet 48 becomes energized and attracts its armature at the repeating station F, which causes the selector lever to return to its normal position. restoring the repeating contact members 55 to their normal positions as shown, thus restoring the normal condition of current in line 43, which returns terminal station E to its normal condition. All needed motors having been started by this operation of interrupting key 46, an operator at terminal station D may send a message. Every movement of transmitter 45 controls magnet 48 to repeat the movement, and magnet 48 in turn controls its cam drum and repeater selector lever to operate the repeating contact members 55 which, when thus controlled, repeat into line 43 every signal generated in line 42 bytransmitter 45, thereby repeating at terminal station E all signals originated at terminal station D. Meanwhile, operation of repeating contact 52 and contact 56 has switched the circuit of magnet 49 which had extended from battery, through magnet 49 and contact 52, to line 43 and to ground at terminal station E. In the operation of contact members 55, contact 56 is closed before contact 52 is opened, thus providing a substitute circuit for magnet 49, extending from battery, through magnet 49, and contact 56 to ground. The substitute circuit constitutes a reflection estoppel circuit and magnet 49, therefore, does not repeat any transmission signals into the line 42. Interruption of transmission may be effected by opening the interrupting key at terminal station E for a short period of time, thus opening the line 43 whereupon either forthwith or at the end of the instant signal, if spacing, the open line 43 will deenergize the line magnet 49, which will start its associated motor and operate its associated repeater to open the line 42, after which the printer 44 at terminal station D will be unresponsive to the transmitter 45 since no current can flow in line 42, by which non-response of the printer 44, the operator at terminal station D will note that terminal station E is interrupting and desires to transmit.

According to Fig. 2, reflection estoppel is effected from either receiving mechanism by energizing under local control the line signal relay or magnet of the companion mechanism, thus contact 56 closes a. local circuit to energize magnet 49.

During all interchange of transmission between the two terminal stations D and E, all transmission originated at station D will operate magnet 48 of printer 54 and will be recorded upon printer 54, while all transmission originated at terminal station E will operate magnet 49 and will be recorded upon the printer of magnet 49. Thus, at the repeating station F, the direction of transmission, whether from terminal station D or terminal station E, will be indicated and identified by the identity of the printer at station F upon which the transmission will have been recorded.

Although the invention has been described in connection with a specific form thereof, it will be understood that it has further applications and it is not intended to be limited in scope by the embodiment shown herein for illustration.

What is claimed is:

1. In a single-line two-way telegraphic repeating system, the combination of a line divided into two sections, two motor-driven repeaters connected intermediate said sections either of which may be started into operation by a received signal condition, motor-operated contacts in said repeaters operated upon starting of one of said repeaters and operating for each received spacing signal condition to restrain the other of said, repeaters against starting, and further motor-operated contacts operable in said started repeater and operating to repeat said spacing signal conditions from one line section to another.

2. In a two-way repeating system, two line sections, rotary regenerative repeaters in said line sections, polarized signal receiving line magnets in said repeaters, retransmitting contacts in said repeaters, a plurality of sources of current of variant potentials and polarities, a signal-receiving circuit including one of said line sections, one of said magnets and one of said sources, and a retransmitting circuit including one of said line sections, one of said contacts and two of said sources of different potentials in polar opposition, said included magnet being responsive to a received spacing signal to operate said included contacts to form said retransmitting circuit.

3. In a two-way repeating system, two line sections, rotary regenerative repeater mechanisms in said line sections, polarized signal receiving line magnets in said repeater mechanisms, retransmitting contacts in said repeater mechanisms, a plurality of sources of currents of equal potential and of different polarities and remote from said repeater, a single source of current of greater potential at said'repeater, and circuits including said sources, said contacts and said magnets, said magnets being responsive to polar signals received over said line sections from said remote sources and effective to operate said contacts to produce regenerated polar retransmission signals in said line sections including said source of current of greater potential.

4. In a telegraph repeating system, two line sections, a motor-driven signal repeater, circuits connecting said repeater to said two line sections, mechanically operated first contacts in said repeater for retransmitting a code signal impulse by impulse into one of said two line sections, a further motor-driven signal repeater, a reflection estoppel circuit including said further repeater, further contacts operated by mechanical power impulse by impulse in said first mentioned repeater, and means for operating said further contacts upon receipt of each spacing impulse and before operation of said first mentioned contacts to establish said reflection estoppel circuit before beginning retransmission of said spacing impulse in said one of said two line sections.

5. In a telegraph repeating system, two line sections, a motor-driven signal repeater, circuit: connecting said repeater to said two line sections, motor-driven means in said repeater for retransmitting code signals impulse by impulse in one of said two line sections, a reflection estoppel means, and motor-operated means in said repeater operative upon receipt of each spacin impulse to establish said reflection esto cl means before beginning retransmitting of spacing impulse in said one of said two line sections.

6. In a telegraph repeating system, two line sections, a motor-driven signal repeater, circ its connecting said repeater to said two line sections. motor-driven means for establishing a reflection estoppel condition in response to each rec ed spacing signal for duration of the spacing signal, and motor-driven means subsequently operated in said repeater to begin retransmission of received spacing signal.

'7. In a telegraph repeating system, two line sections, rotary regenerative repeater mechanisms in said line sections, polarized signal receiving line magnets in said line sections, re-

transmitting contacts in said repeater mechanisms, a plurality of electrical sources of different polarities and of uniform potential, a further electrical source of greater potential, and means responsive to reversal of polar signal in one of said line sections operative to include said further source in the other of said line sections in polar opposition to one of said first mentioned electrical sources to efiect a reversed polar signal.

8. In a telegraph repeating system, the combination of two line sections, two combinedsignal-recording and signal-repeating mechanisms,

one in each of said line sections and each having motor-driven signal-repeating contacts and 'an operating magnet operable under control. of its associated one of said two line sections, and a circuit controlled by said signal-repeating contacts in one of said two mechanisms and including said operating magnet in the other of said two mechanisms and operating to retain said magnet againstresponse to operation of said signal-repeating contacts.

9. In a telegraph repeating system, two line sections, two line relays, one for each line section, two combined signal-recording and signalrepeating mechanisms, one for each of said line sections and each operable by its associated one of said two line relays, and means controlled'by signal-repeating contacts in one of said two mechanisms and including both signal-repeating and signal-recording elements of the other of said two mechanisms to disable both said signalrepeating and signal-recording elements in response to operation of said signal-repeating contacts.

LOUIS M. PO'ITS. 

